1. Technical Field
The invention relates to a system for simulating sound engineering effects. More particularly, the invention relates to an audio signal processing system that simulates sound engineering effects that were produced when a sound was previously created and processed for recordation.
2. Related Art
Digital signal processing techniques may replace analog signal processing techniques or provide additional processing of an analog signal. Digital audio signals have started to replace what have traditionally been analog audio signals, such as recordation of digital audio signals on compact discs instead of analog audio signals recorded on LP records. Reproduction, modification, creation, recreation, etc. may be easier, simpler and more accurate with digital audio signals rather than with analog audio signals, even with the quantization noise that may be present in digital signal processing. Accordingly, digital signal processing techniques heavily affect the music industry and among other things, musical instruments such as an electric guitar.
An electric guitar is typically coupled to an amplifier and one or more loudspeakers. The amplifier and the loudspeakers may be either separate devices or combined in a single unit. The amplifier may be a tube amplifier that uses traditional vacuum tubes to process audio signals in the analog domain. These tube amplifiers are still widely used because many musicians are of the opinion that a tube amplifier provides a musically superior, “warm” sound. Despite having desirable sound qualities, the tube amplifier has disadvantages and limitations that result from operation in the analog domain. To overcome these limitations, digital signal processing techniques have been used to simulate a tube amplifier.
Simulation of a tube amplifier typically focuses on simulation of the tonal characteristics of the tube amplifier. The tonal characteristics of the tube amplifier may result from distortion of an audio signal during processing. Distortions may occur when the tube amplifier is overloaded, overdriven and/or somewhat intentionally misused, for example, by connecting an output of one tube amplifier to an input of another tube amplifier. These types of distortion may be the reason why the tube amplifier produces a musically appealing sound. For example, tube amplifiers manufactured by Fender Musical Instruments Corp. are well known and may be recognizable by their signature distortions. Simulation or modeling of a Fender tube amplifier using digital signal processing techniques may produce this signature distorted sound. Various types of amplifier simulators may be made and used to produce the desirable distortion. In addition, warping between multiple different amplifier simulators may be implemented.
Despite developments of simulation or modeling techniques that simulate the desired tonal characteristics of the tube amplifier, no simulation and modeling techniques may attempt to simulate sound engineering effects that one hears on a medium such as a sound recording. In addition, the simulation or modeling techniques focus on an electric musical instrument such as an electric guitar and do not extend to an acoustic musical instrument such as an acoustic guitar or vocal sound. Accordingly, there is a need for a system for simulating sound engineering effects that is applicable to both electric and acoustic musical instruments.